Limonade: README

Limonade is a PHP micro framework for rapid web development and prototyping.

It’s inspired by frameworks like Sinatra or Camping in Ruby, or Orbit in Lua. It aims to be simple, lightweight and extremly flexible.

Limonade provides functions that complete the PHP basic set, while keeping consistency with native functions and sitting up on them.

Limonade is easy to learn and provides everything that you can expect from a modern framework (MVC, REST, …)

require_once 'lib/limonade.php';
dispatch('/', 'hello');
    function hello()
        return 'Hello world!';

About this document

This document provides a quick, but comprehensive, guide of Limonade features.

For more informations, you can see the website, public API documentation, examples, and of course the source code which is still the best documentation.

A discussion group is also available for more exchanges.


Routes combine

So they make the glue between an URL + a HTTP method, and the code provided in a callback controller.

dispatch('/', 'my_get_function');
# same as dispatch_get('my_get_function');
    function my_get_function()
        // Show something
        // with the code of this callback controller

dispatch_post('/', 'my_post_function'); 
    function my_post_function()
        // Create something

dispatch_put('/', 'my_update_function'); 
    function my_update_function()
        // Update something

dispatch_delete('/', 'my_delete_function'); 
    function my_delete_function()
        // Delete something

Routes are matched in the order they are declared. The search is performed with a path given through browser URL:


When PUT or DELETE methods are not supported (like in HTML form submision), you can use the _method parameter in POST requests: it will override the POST method.

<form action="<?php echo url_for('profile_update'); ?>" method="post">
    <p><input type="hidden" name="_method" value="PUT" id="_method"></p>
    <p>... your form fields</p>
    <p><input type="submit" value="Update"></p>

Routing patterns and parameters

Patterns may include named parameters. Associated values of those parameters are available with the params() function.

dispatch('/hello/:name', 'hello');
    function hello()
        $name = params('name');
        return 'Hello $name';

Patterns may also include wildcard parameters. Associated values are available through numeric indexes, in the same order as in the pattern.

dispatch('/writing/*/to/*', 'my_letter');
    function my_letter()
        # Matches /writing/an_email/to/joe
        $type = params(0); # "an_email"
        $name = params(1); # "joe"
        # ...

dispatch('/files/*.*', 'share_files');
    function share_files()
        # matches /files/readme.txt
        $ext = params(1);
        $filename = params(0).".".$ext;
        # ...

Unlike the simple wildcard character *, the double wildcard character ** specifies a string that may contain a /

dispatch('/files/**', 'share_files')
    function share_files()
        # Matches /files/my/own/file.txt
        $filename = params(0); # my/own/file.txt

Pattern may also be a regular expression if it begins with a ^

dispatch('^/my/own/(\d+)/regexp', 'my_func');
    function my_func()
        # matches /my/own/12/regexp
        $num = params(0);

Wildcard parameters and regular expressions may be named, too.

dispatch(array('/say/*/to/**', array("what", "name")), 'my_func');
    function my_func()
        # Matches /say/hello/to/joe
        $what = params('what');
        $name = params('name');

You can also provide default parameter values that are merged with and overriden by the pattern parameters.

$options = array('params' => array('firstname'=>'bob'));
dispatch('/hello/:name', 'hello', $options);
    function hello($firstname, $name) # default parameters first
        return 'Hello $firstname $name';

Callback controllers

The callback can be a function, an object method, a static method or a closure. See php documentation to learn more about the callback pseudo-type.

# will call my_hello_function() function
dispatch('/hello', 'my_hello_function');

# Static class method call, MyClass::hello();
dispatch('/hello', array('MyClass', 'hello'));

# Object method call, $obj->hello();
dispatch('/hello', array($obj, 'hello'));

# Static class method call (As of PHP 5.2.3), MyClass::hello();
dispatch('/hello', 'MyClass::hello');

# Using lambda function (As of PHP 5.3.0)
dispatch('/hello', function(){
  return 'Hello World!';

Callback controllers return the rendered view output (see Views and templates).

They can take the pattern parameters as arguments

dispatch('/hello/:firstname/:name', 'hello');
    function hello($firstname, $name)
        # $firstname parameter equals params('firstname');
        # and $name parameter equals params('name');
        return 'Hello $firstname $name';

Callbacks called by routes can be written anywhere before the execution of the run() function. They can also be grouped in controller files stored in a controllers/ folder.

/                   # site root
 - index.php        # file with routes declarations and run()
 + controllers/
     - blog.php     # functions for blog: blog_index(), blog_show(),
                    #  blog_post()...
     - comments.php # comments_for_a_post(), comment_add()...

This folder location can be set with the controllers_dir option.

option('controllers_dir', dirname(__FILE__).'/other/dir/for/controllers');

You can also define autoload_controller function to load controllers in your own way:

function autoload_controller($callback) 
   # If $callback, the callback function defined in matching route, 
   # begins with 'admin_', then we load controllers from
   # the admin sub-directory in the controllers directory.
   # Else we load controllers the normal way from 'controllers_dir'.

   $path = option('controllers_dir'); 
   if(strpos($callback, "admin_") === 0) $path = file_path($path, 'admin'); 

Url rewriting

Since version 0.4.1, Limonade supports url rewriting.

With a .htaccess in your app folder

<IfModule mod_rewrite.c>
  Options +FollowSymlinks
  Options +Indexes
  RewriteEngine on

  # if your app is in a subfolder
  # RewriteBase /my_app/ 

  # test string is a valid files
  RewriteCond %{SCRIPT_FILENAME} !-f
  # test string is a valid directory
  RewriteCond %{SCRIPT_FILENAME} !-d

  RewriteRule ^(.*)$   index.php?uri=/$1    [NC,L,QSA]
  # with QSA flag (query string append),
  # forces the rewrite engine to append a query string part of the
  # substitution string to the existing string, instead of replacing it.

And setting explicitly the option('base_uri') in your configure() function:

option('base_uri', '/my_app'); # '/' or same as the RewriteBase in your .htaccess

You can access your site with urls like instead of

Views and templates

Template files are located by default in views/ folder. Views folder location can be set with the views_dir option.

option('views_dir', dirname(__FILE__).'/other/dir/for/views');

To pass variables to templates, we use the function set ()

set('name', 'John Doe');

Variables may also be passed directly:

render('index.html.php', null, array('name' => 'John Doe' ));

set_or_default function allows passing a variable, and if it’s empty, a default value. It is really useful for the assignment of optional parameters extracted from the url using the params() function.

dispatch('/hello/:name', 'hello');
    function  hello()
        # matching /hello/
        set_or_default('name', params('name'),'John');
        return render('Hello %s!'); // returns 'Hello John!' because params('name') was empty. Else it would have returned params('name') value.

As you can notice, final output is returned by your controller. So remember to explicitly return your view in your controller with the return keyword! (This remark will be particularly helpful for rubyists ;-) )


Templates may be rendered inside another template: a layout.

Layout may be set with the layout function:


or directly with the template rendering function

render('index.html.php', 'default_layout.php');

If layout value is null, rendering will be done without any layout.

render('index.html.php', null);

Formatted strings and inline templates

Formatted string can be used like with sprintf:

set('num', 5);
set('where', 'tree');
return render('There are %d monkeys in the %s') // returns 'There are 5 monkeys in the tree'

It’s also possible to provide a function name as a template. By this way, for example, we can produce a single file application.

function html_message($vars){ extract($vars);?>
    <h1>Title: <?php echo h($title); ?></h1>
       <?php echo h($msg); ?></p>

// in a request handling function
set('title', 'Hello!');
set('msg', 'There are 100 monkeys in the Chennai and bangalore');
return render('html_message');

HTML Templates

html function is used in the same way as render. A header specifies the proper HTTP Content-type (text/html) and encoding setting defined through options (utf8 by default).


Templates XML

xml function is used in the same way as render. A header specifies the proper HTTP Content-type (text/xml) and encoding setting defined through options (utf8 by default).


Templates CSS

css function is used in the same way as render. A header specifies the proper HTTP Content-type (text/css) and encoding setting defined through options (utf8 by default).


Templates JS

js function is used in the same way as render. A header specifies the proper HTTP Content-type (application/javascript) and encoding setting defined through options (utf8 by default).


Templates TXT

txt function is used in the same way as render. A header specifies the proper HTTP Content-type (text/plain) and encoding setting defined through options (utf8 by default).


Templates JSON

json is used the same way as json_encode function, and returns a string containing the JSON representation of a value. A header specifies the proper HTTP Content-type (application/x-javascript) and encoding setting defined through options (utf8 by default).


Serving files

The render_file function can render a file directly to the ouptut buffer.


A header specifies the proper HTTP Content-type depending on the file extension, and for text files, encoding setting defined through options (utf8 by default) .

Output is temporized so that it can easily handle large files.


The partial function is a shortcut to render with no layout. Useful for managing reusable blocks and keeping them in separate files.

This code

partial('my_posts.php', array('posts'=>$posts));

is the same as

render('my_posts.php', null, array('posts'=>$posts));


The content_for function allows you to capture a block of text in a view. Then the captured block will be available for the layout. This is useful for management of layout regions like a sidebar or to set javascript or stylesheet files that are specific to a view.

For example with this layout:

<div id="content">
  <div id="main">
    <?php echo $content; ?>
  <div id="side">
    <?php if (isset($side)) echo $side; ?>

And in your view:

<p>My main content</p>

<?php content_for('side'); ?>
  <li><a href="<?php echo url_for('/pages/item1')?>">Item 1</a></li>
  <li><a href="<?php echo url_for('/pages/item2')?>">Item 2</a></li>
<?php end_content_for(); ?>

Rendered result is:

<div id="content">
  <div id="main">
    <p>My main content</p>
  <div id="side">
      <li><a href="?/pages/item1">Item 1</a></li>
      <li><a href="?/pages/item1">Item 2</a></li>

The above example is detailed in this tutorial.

Use captures with partials, it will help you to organize your views and will keep you from having to copy/paste the same code many times.

Hooks and filters

Limonade allows the user to define some functions to enhance the Limonade behaviour with its own needs.

Some of those, like the before hook and the after filter are commonly used, and others are only for advanced usage that might require a good comprehension of Limonade internals.


You can define a before function that will be executed before each request. This is very useful to define a default layout or for passing common variables to the templates.

function before($route)
    set('site_title', 'My Website');

The current matching route is also passed to the before function, so you can test it. It’s an array as returned by the internal route_find function, with these values:


An after output filter is also available. It’s executed after each request and can apply a transformation to the output (except for render_file outputs which are sent directly to the output buffer).

function after($output){
  $config = array('indent' => TRUE,
                  'output-xhtml' => TRUE,
                  'wrap' => 200);

  $encoding = strtoupper(str_replace('-','', option('encoding')));
  $tidy = tidy_parse_string($output, $config, $encoding);
  return $tidy;

The current executed route is also available for after function.

Before render

You can define a before_render function that will filter your view before rendering it.

The first three parameters are the same as those passed to the render function:

Last parameter, $view_path is by default file_path(option('views_dir'), $content_or_func);

function before_render($content_or_func, $layout, $locals, $view_path)
  # Transform $content_or_func, $layout, $locals or $view_path.
  # Then return there new values
  return array($content_or_func, $layout, $locals, $view_path);


You can define your own autorender function to make automatic rendering depending on current matching route. It will be executed if your controller returns a null output.

dispatch('/', 'hello');
function hello()
    # process some stuff...
    set('name', 'Bob');

    # but don't return anything
    # ( like if you were ending this function with return null; )

function autorender($route)
    $view = $route['callback'] . ".html.php";
    return html($view);

In this example, when url / is called, hello() is executed and then autorender() renders the matching hello.html.php view.

Before exit

If you define a before_exit, it is called at the begining of the stop/exit process (stop_and_exit function called automatically at Limonade application termination).

function before_exit($exit)
    # $exit is the same parameter as the one passed to `stop_and_exit`.
    # If it's false, the exit process will not be executed, 
    # only the stop instructions
    # by default it is true


You can define a configure that will be executed when application is launched (at the begining of the run execution). You can define options inside it, a connection to a database …

function configure()
    $env = $_SERVER['HTTP_HOST'] == "localhost" ? ENV_DEVELOPMENT : ENV_PRODUCTION;
    option('env', $env);
    if(option('env') > ENV_PRODUCTION)
        options('dsn', 'sqlite:db/development.db'));
        options('dsn', 'sqlite:db/production.db'));
    $GLOBALS['my_db_connexion'] = new PDO(option('dsn'));

PHP files contained in the option('lib_dir') folder (lib/ by default) are loaded with require_once just before executing configure. So you can place in this folder all your PHP libraries and functions so that they will be loaded and available at application launch.


The option function allows you to define and access the options of the application.

option('env', ENV_PRODUCTION);
option('env'); // return ENV_PRODUCTION value

If the name of option is not specified, it returns an array of all the options set.

You can use it to manage Limonade options and your own custom options in your application.

Default Limonade options have the following values:

option('root_dir',        $root_dir); // this folder contains your main application file
option('base_path',          $base_path);
option('base_uri',           $base_uri); // set it manually if you use url_rewriting
option('limonade_dir',       dirname(__FILE__).'/'); // this fiolder contains the limonade.php main file
option('limonade_views_dir', dirname(__FILE__).'/limonade/views/');
option('public_dir',         $root_dir.'/public/');
option('views_dir',          $root_dir.'/views/');
option('controllers_dir',    $root_dir.'/controllers/');
option('lib_dir',            $root_dir.'/lib/');
option('error_views_dir',    option('limonade_views_dir'));
option('env',                ENV_PRODUCTION);
option('debug',              true);
option('session',            LIM_SESSION_NAME); // true, false or the name of your session
option('encoding',           'utf-8');
option('x-sendfile',         0); // 0: disabled, 
                                 // X-SENDFILE: for Apache and Lighttpd v. >= 1.5,
                                 // X-LIGHTTPD-SEND-FILE: for Apache and Lighttpd v. < 1.5


Session starts automatically by default. Then you can access session variables like you used to do, with $_SESSION array.

You can disable sessions with the session option.

⌘ see snippet example


Flash is a special use of sessions. A flash value will be available only on next request and will be deleted after. It’s very useful to raise errors on a form or to notice a successful action.

⌘ see snippet example


See sources or api for more about all available helpers.


You can use the url_for function for rendering limonade urls. They will be well formed from whatever folder in the document root your application is installed on your web server.

# with option('base_uri', '?')
url_for('one', 'two', 'three'); # returns ?/one/two/three
url_for('one', 'two', array('page' => 1)); # returns ?/one/two&amp;page=2

If you want to use url rewriting, you need to explicitly set the base_uri option ( default is /your_file_path/?)

Halting and error handling


You can stop immediately the execution of the application with the halt function. Errors will be handled by default Limonade error handlers or those you have defined.

halt("En error occured in my app...");

Not Found

By default, displays the not_found error output function and sends a 404 NOT FOUND HTTP header.

halt(NOT_FOUND, "This product doesn't exists.");

To define a new view for this error, you can simply declare a not_found function.

function not_found($errno, $errstr, $errfile=null, $errline=null)
    set('errno', $errno);
    set('errstr', $errstr);
    set('errfile', $errfile);
    set('errline', $errline);
    return html("show_not_found_errors.html.php");

Server Error

By default, displays the server_error error output function and sends a 500 INTERNAL SERVER ERROR HTTP header.

halt('Breaking bad!');
halt(SERVER_ERROR, "Not good...");
trigger_error("Wrong parameter", E_USER_ERROR);

PHP errors are also caught and sent to this error handler output.

To define a new view for this error, you can simply declare a server_error function.

function server_error($errno, $errstr, $errfile=null, $errline=null)
    $args = compact('errno', 'errstr', 'errfile', 'errline');   
    return html("show_server_errors.html.php", error_layout(), $args);

Error layout

Allows you to define and access a layout dedicated to errors.

error_layout(); // return 'error_layout.php'

Error handling

In addition to the common NOT_FOUND and SERVER_ERROR error displays, Limonade can redirect precise errors to your own functions.

error(E_USER_WARNING, 'my_notices')
    function my_notices($errno, $errstr, $errfile, $errline)
        // storing php warnings in a log file
        // ...
        return html('<h1>Server Error</h1>');

E_LIM_HTTP means all HTTP errors

error(E_LIM_HTTP, 'my_http_errors')
    function my_http_errors($errno, $errstr, $errfile, $errline)
        return html('<h1>'.http_response_status_code($errno).'</h1>');

E_LIM_PHP means all PHP errors (sent by PHP or raised by the user through trigger_error function).

Other useful functions

Limonade also provides a useful set of functions that can help you managing files, HTTP… For more about those utilities, see the source code at section 7. UTILS.